Reversible electric control system



. Slept. 23, 1952 G, F, RlCHARDS 2,611,888

REVERSIBLE ELECTRIC CONTROL SYSTEM Filed Jan. 7, 1950 2 SHEETS-SHEET lINVENTOR. lL-ORGE /P/CHA pas ATTORNEK Sept. 2 3, 1952 G. F, RlCHARDs2,611,888

REVERSIBLE ELECTRIC CONTROL SYSTEM Filed Jan. 7, 195o 2 SHEETS- SHEET 222 231 ENQ( 274 wt ff/ l v 25 I 276' 277 273ml.

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IN VEN TOR. faef E HCH/9R05 Patented Sept. 23, 1952 2,611,888 REVERSIBLEELECTRIC ooNT-RoL SYSTEM George F. Richards, Garden City, N. Y.,assignor to Teletronics Laboratory, Inc., Westbury, N; Y.; a corporationof New York H i Y Application January 7, lssogs'erisiNo.,1s*1,410\

9 claims. (o1. sis- 202) f 1 The present invention relates to automaticcontrol systems, and particularly to systems for propulsion of amovableobject between a plurality of predetermined positions.

In particular, an object of the present invention is the provision of acontrol system suitable for controlling the propulsion of an object suchas a lgarage door between two limiting positionsthe fully closed doorposition and the fully opened position. s

A special feature of this invention is the elimination of extensivereliance upon limit switches, theV apparatus being arranged to be turnedoi and reset for a further operation by deceleration of the motor due tothe physical resistance met as the garage `door or other movable objectarrives at the limit of its travel.

A further feature is the organization ofl the` position for an impulsetransmission. An ac-v companying feature is the arrangement of thecircuit to stop the movable object in response to a momentary local orremote control circuit actu'- ation signalled While the object is beingpropelled, and to reset the circuits to cause its propulsion in responseto the next signal. When the object is slowed down by its encounter withincreased resistance, the propulsion circuit not only is stopped inresponse to decelerated motor operation but also the control circuitsare reset to provide for institution of propulsion in the oppositedirection uponi the receipt of a further control impulse.

s In lmy copending patent application Serial No. 45,759 led August 23,1948, of which the present application is a continuation-in-part, thereis described a door control system including a reversible electric motorbelt-coupled to the counterspring shaft of a sectional garage door ofthe type which is raised upward and inward of the garage, the door beingguided by rollers operating in a pair. of tracks having Verticalsections at the sides lof the door opening and'slightly inclinedsections within the garage.

o In the aforementioned application, circuits were provided for havingthe motor normally start in the direction for raising the door, from anyposition otherr than its fully raised position.y

The vvpropulsion system was arranged to be stopped by a set of camswitches operated as the door arrived at the top of its travel, theseswitches, being varranged to be held in a reversed-starting condition insuch a way as to provide downward doorpropulsion upon a followingoperation of the system. It depended upon the cam being so situatedas tohold the switches inthe reverse--` starting throw position until aftervthe motorhad` accelerated beyond the speed at lvvhichuit had opened thecircuit to its direction-controlling starting winding through theoperation of its centrifugal switch. To this extent, the system of saidprior application was dependent upon accurate placement of one cam andupon speed and load characteristics of the motor andits load.

In its ,downward drive, on the other hand, it was load-responsive, to bestopped by excessive resistance, and was arranged for upward travel uponthe next operation by virtue of its normal (upward propulsion)directional circuit beingundisturbed with the door cam remote fromA thecam switches.- Y y j In this application are shown three lcontrol systemembodiments which are entirely stepcyclic in rtheir operation, and arefree fromgreliance upon any cam switches or travel Vlimit switches.

One momentary circuit actuation whenfthe` door is at rest sets upcircuits driving it untilit reaches its normal travel limit `or isotherwise,

obstructed. Another momentary circuit actuation sets up circuits drivingthe door in the op-l` posite direction until it reaches its normaltravel limit or is sooner obstructed. A control circuit actuation duringpropulsion has the` effectsof stopping the propulsion system andresetting it` for the opposite direction whichever was 'thedi--j rectionof travel at the time. of interruption.

Maximum safety of operation is achieved inthisV ditions, e. g. to an icelayer formed on the aprony and raising the lower contactpoint of thedescending door, or even a shift in position of the 1 upper travel stopof the door. Three embodiments of the invention are vshown in Figs. 1,2'and 3, and Fig. 4 shows details cfaI sequence stepping relay usable inthe embodi-y ment of Fig. 3.

In each of these embodiments, the motor will'` be described as coupledto a sectional garagexdoor i by a belt from speed reduction` gears ofthe mtor.

to the counterspring shaft of the door, -as illus-w trated in theaforementioned parent 'application Serial No. 45,759, the doorbeing-limited inits upward travel by track stops and 'in `its descentbyMoreover, it enjoys a 3 the garage oor. It will be appreciated that thecontrol system is applicable also to other objects movable betweenopposite limits of travel.

The control circuit arrangement of Fig. 1 comprises a low voltage A. C.relay I0, a first line voltage A. C. relay 20 and a second line voltageA. C. relay` 30, and a D. C. operated sequence stepping relay 40. RelayI includes a normally open contacter IBA, and a double throw contactarrangement including a normally open contactor IUB and a normallyclosed contacter IUC. Relay 20 includes a double throw contacterincluding a normally closed contacter arrangement 20A, a normally opencontacter arrange-- ment 20B and a pair of additional normally opencontactors 20C and 20D. Relay Bilincludesf'aiy first double throwcontact arrangement having a normally closed contacter 30A and anormally open contacter 30B, a second double throw contacter including anormally closed contacter 30D and normally open contacter 30C andanadditional normally open contacter 30E. Relay 40': is'provided withdouble-pole double-throw switching arrangements, forreversiblyconnecting theA. C. supply mains to the running Winding ofthe motor, aswill presently be described. f A-voltagestep-down transformer I2 isarranged with its-primary winding connected to the power supply plug I3through a thermal cutout I4 on motor I 5,V and-a fuse I6 included'as anadded protective device in the lineA circuit.

The low voltage secondary winding of transformer I2 is connected to thecoil'of relayl through push button switch I1, which is normally open,vand is arranged to be depressed momentarily.

The motor I is illustrated vas a single phase induction motor of thetype having a running Winding I8 and a starting winding I9, the motorbeing provided also with a centrifugal starting switch 2| arranged toopen the starting winding circuit as-'the rotor is accelerated beyond apredetermined speed. The direction of operation of Ythemotorvisdependent upon whether the windings I8 and I9 are suppliedcophasa-llydurf ing star-ting, or in opposite phase. The'illustratedcontrol circuit, as will presently be described', is

arranged for starting of -the motor rst in -onel direction, and fersubsequent starting thereof in the' opposite direction,l within oneVcomplete operating cycle of the system.

- Afvariable resistor 22 is included in the circuit through whichthe-'running `winding of the'motor receives its current supply, thisresistorbeing provided to enable the user te preset the motoroperatingconditiom for desiredv torque-speed'v characteristics,suiiicient resistance -being introduced by the adjustment of rheostat 22to insure that the motor speed willbe reduced sufliciently toibringaboutthe reclosure of switch 2I withV a torque load exceeding by a reasonablysmall margin the normal running torque of the system. Such a speedreduction of the motor will hereafter be referred to `as a stallingthereof.

The rotor of motor I5 is coupled through speedreduction systempreferably including a gear trainand a V-belt drive, to aY pulleyattached to the counterspring shaft of a sectional overhead door of agarage in the manner described inzmy copending patent applicationsSerial No. 45;'159 iiled August 23, 1948, and Serial No. '79,215

iiledMarch 2, 1949, the present application being'afzcontinuation-in-part of the fermer, as heretofore-.pointed out.

A..dry' 'disc.rectier 23 and a capacitor 24 arev Y and the specialcyclical operation in response to successive momentary depressions ofswitch I1 will new be brought out more fully in the description of theoperation of the system.

The .conditions of the circuit elements as illustrated, with all relaysin their relaxed or nonenergized conditions and with lamp 25illuminated, correspondto the conditions with the garagedoor open, andat rest at the top of its travel. Now, switch I'I (or a normally opencontactor of a remote control radio receiver output relay in paralleltherewith) is momentarily closed tostart the downward drive of thegarage door. The closure of this switch operates relay I0. and throughcontacter 30D and contacter IDA', relay 25'is energized. New,alternating'voltage issupplied from alternating current conductor 3l,through arm 4I cf relay 4D, through con"- tactor 20D, te the motorrunning windingV terel minal 32, and the other motor runningwindinglterminal 33 is supplied through arm 42 of relay 40, through contacter20C. As the motor start-l ing winding I9 is supplied through aconnection in `parallel with'the coil of relay 20, the'motor commencesto drive the garage door downward. It quickly accelerates beyond'thepredetermined speed atwhich switch 2I is automatically opened,l

and thereafter switch Il is released, opening the circuit of relay ID.Relay 2liV is not deenergized at this point,A however, because a holdingcircuit contact arm connected to lamp 25 is transferredv to the positionclosing contacter 30B, causing,

the lamp 25 to wink off and immediately onfagain,

with its supply brought through this circuit .in-- stead of the previouscircuit through contacter. Also contacter 30D is opened.

30A, as before. and contactors 30E and 30C are closed.

New the motor I5 continues to drive the garageY door downward until thedoor encounters appreciable increased resistance to its descent, the`condition which normally occurs at complete closure of the door. At thatpoint, centrifugal speed-responsive switch 2| reclosesk because Aof thestalling of motor tween supply main 3I and the terminal 28 of .relay 20.As the opposite coil terminal is permanentlyru connected to supply main3| this effectively' tact arms of relay 20, so that contacter 20A"re`closes and the remaining contactors arereopened,

the holdingY circuit condition'for this Yrelay being ended.-

Accordingly, thisi I5, and, through the very low resistance of startingwinding I9', asubstan tially short-circuiting shunt path is providedbef-- -Withthe opening of contactor 20B,..further` more, the alternatingcurrent supply circuit for the coil of relay 30, which proceededthencethrough contactor IOC and contactor 30E, ink

parallel, was opened, leaving relay 30 deenergized. Withsarms 4| and 42of relay 40v transferred to their yleft-hand throw, the alternatingcurrent.

circuit connections for motor running coil supply terminals 32 and 33are reversed, terminal `33 being connected to supply main 3 I..Accordingly, the next starting operation to be institutedmust causemotor I5 to commence operation in the opposite direction, i. e. to raisethe garage door. The lamp 25 is deenergized, as aforementioned, sinceits circuit through reclosed contactor 30A proceeds now through contactarm 4| transferred to the left, and encounters an open circuit conditionat contactor 20C.

From the foregoing description, it is seen that the reclosing of switch2| as motor I5 stalled in driving the door downward caused the reopeningof the supply circuits of relays 20 and 30, and that the reopening ofcontactors 20C and 20D broke the supply circuit to running winding I8,starting winding I9 also being left deenergized with contactor 20B open.

With this circuit arrangement, the centrifugally operated speedresponsive switch 2| of motor I5 serves an automatic control function,in such a way ,that no lower limit switch is required, and in such a wayalso that a special safety factor is provided in that the system will bestopped short of the full closure of the door if it encounters anabnormal distribution such as the body of an automobile, or a childsvehicle left in the way, or a human body.

Ifit were desired to stop the downward proi pulsion of the garage doorprior to the stalling of motor I5, switch I1 could be momentarilydepressed to accomplish this purpose. Depression of this switch whilemotor I5 was driving the door downward would again energize relay I0,providing a circuit from supply main 3| through contactor 30C andcontactor IIIA to'terminal 28 of relay 20, shorting out the supplycurrent of this coil and opening relay 20, to deenergize the motorasaforementioned. Until the release of switch I'I and the deenergizationof relay I0, relay 30 remains energized even after the opening of relay20. Upon release of switch I1, relay I0 is released, and the consequentopening of contactor IOB interrupts the energiza-` tion circuit throughcontactor 30E, so that relay 30 is deenergized. The discharge ofcapacitor 24 through the coil of relay 40 takes place in this instanceupon the reclosure of contactor 20A, just as aforedescribed in responseto reclosure of switch 2| due to the stalling of motor I5.

4It will be observed that the system is left in thewsame set ofconditions, whether the downward drive of the garage door is stopped bythe normal stalling of motor I5, or stopped at an intermediate levelbymomentary depression and releaseoi switch I'I. x: f i

6 Now, when next it is desired to causethe dees* to be opened, switch I1isagain depressedmenerg1 Y.: gizingy relay I0, and again-energizingrelay 20,'. through contactors 30D and.l IOA, andprovidingI a holdingcircuit forrelayY 20 through contactor l 20B and resistor 35. f u 7Starting winding I9 is energized concurrently with the supply of thealternating current power to the coil of relay 20, and running windingI8,-is t immediately thereafter supplied through; con-l tactors 20C and20D, through contact-.arms 4t; and 42 of relay 40 in their left-handthrow-sp that the energization of the motor is in thephase relation toprovide upward drive of the garage, door, commencing immediately. Again,the motor is promptly accelerated beyond the speed at which switch 2|opens prior to the release of switch I'I, and when switch I1 isreleased, relay 30-is again#l energized through contactor 20B and IOC.Lamp l 25 is thereupon illuminated through contacterI The upward driveof the garage door may be stopped at any desired intermediate doorpositionby momentary depression of kswitch II. This temporarilyenergizes relay I0, bringing terminal i 28 of relay 20 to the potentialof supply conductor 3i through contactors 30C andA IIJA as. afore-VVdescribed, deenergizing relay 20 and also causing I the restoration ofganged arms 4| and 42 of relay.; 40 to the right-hand throw by virtue ofthe discharge of capacitor 24 through -contactor 2IlAf. and the coil ofrelay 40. Relay 30 as before re. mains energized after the openingofrelay 201,4 until switch I1 is released, the supply to relay 30then'being broken at contactor I0B. f In the absence of such anoperation of switch II with the door intermediate in its upward` travel,motor I5 drives it all the way to the upper limit of its travel, whereits progress is blocked-,z so that motor I5 is thereupon stalled, withthe result that switch 2 Iis reclosed. 1 s; Again, with the reclosing ofswitch 2 I, the coil of relay ,20 is effectively short-cirouited sothatv relay 40 is energized and relay 30 is deenergized, all elementsofthe circuit being restored to thev conditions as illustrated in Fig.l.

Thus, the present control system permits starting as a result of amomentary depression 'of the control switch, being equally susceptibleof start-5. ing as a result of closure' of a relay contactor"v `shuntingswitch I'I and operated by the output I of a remote control radioreceiver located in the vicinity of the garage door and arranged toreceive a brief carrier transmission from a remote .control transmitter.It is capable oi being arrested at any desired position in its upward ordownward travel by a further momentary closure 'r of switch I'I or aremote control circuit relay. After the arrest of propulsion in onedirectionf.- the circuit arrangement is automatically'reset to bethereafter started by further depression for former I2 and momentarycontact switch ITN?? This relay corresponds to low voltagealternating "fcurrent relay I0 of Fig. 1, except that it islpr'o# vided with anadditional normally open single? pole contactor IIIJD. Y i.. Relay |20Ycorresponds generally to relay 20 of aangaat-2f:

ing lI @opposite :the vterminal there'o'f-l 'connected-"to- Yspeed-responsive switch 2| Y Relay-Bilan Fig. 2 corresponds generally tothrow contactor "system -is eliminated, lea-ving normally-opencontfactors'v |3QE7`and Hill()v and' normallyclosed contactor l 36D.

Figi-'"Zillustrates vthe circuit conditions with allrel'ysdeenergized,the-conditions prevailing f Witt-fthe garage door clc'rsed.4

Coniie'riti-onal relays 'I50an'd' ISU working .to-

getherffare far-ranged to serve the'pur-po'ses of lre layfIlllfofliig.`1, ob'viating this'steppin'g relayV porarily'energizing relay I H3;Relay I2@ is there-vk upon energized through a circuit traceable fromsupply main 3| 'through its coil, and through con-l tactors I IIJA'andISBD, tothe opposite (groundedlfsupply main. With the closure of relayIZI), a fhol'ding 'circuiti is provided `through contactor IZDB andresistor 35.1 At the same time, the starting winding I9 of motor I5is`energized,.-this starting winding and the' internal centrifugalswitch'2l being connected, as before, in series, across the coilv ofrelay |20 and thus being arrangedfor connection 'to thealternating'current supply in only one polarity sensing.

Also,' with contactor |2535 thus closed, the grounded alternatingcurrent supply main is connected'through conductor |23 vto avpair ofoppositely connected stator terminals of the doublepole, double-throwreversing switch armature arrangement'fincluding'arms |6| and |62 ofrelay |60. The otherfstator 'elements of this doublethrowl reversingswitcharrna'ture arrangement are connected zto'the circuitlof supplymainSI to be energized throughthermal cut-out 'I4 and fuse I6 Relay|if|is energized,v through 'the circuit traced-from,supply'conductor 3|through the coil of 'relay |56, through contactor |2052, througharm .16|`of relayl tion, and through conductor |23 and contactor il in its upperthrowv posi- IZOB'y to `the .opposite supply main. A holdingAcircuit-,for relay i5!) providedthrough resistor |35', and .contactor.|5ElB, in a manner similarto the-holding'circuit arrangement of relay|2iin-` volving resistor 35 and contactor .I 2!B.l n

The running .winding I8 of the motorfis ener'- gizedwith j its upperterminal supplied `through contact arm |62 from supply main 3l, and'itslower terminal supplied from the opposite` supply mainthrough contactor128B, conductor |23, arm

|6I orrelay |80 and the yupper statorlcontact element therefor, andresistor 22, provided as in thev arrangement of Fig.` l for presettingthe stall torque characteristics of the motor I5.Y

With-these. circuit conditions established sub-f' stantiallyimmediately; upon 'the Vdepress'ion of-l'f switch I'I, the motor |5promptly '.-commenceSi-i driving the door upwardfandisveryfquickly accelgrated-through: the' arotor spe'ed'at; whichtspeed responsiveAcentriiugally operated! switch" 2| @isf opeilidzl U poni the release'ofswitchl 1 thereafter;

relay. I 0 v4is 'deenergi'zed," with all of' its'contactors` i exce'p'tcontactor'l IIUCwbeing opened'.` Through.y this-latter contactor,-nowreclosed la circuit iisk established forenergization ofV the coiloffrelay.l

I 3U' thr'oughf contactor-1| IJGf` and lI 0C, andfcon'- tactor1|30Dis'thereupon opened and contactors I30C2'and|30Ef'areclosed. The supplyto the running winding `|8fo'f motor I5 is not disturbed by,thiso'peratiom' 'and the motor 'continues' driving` the'` rdoorupward;.f and rlamp .26 is illuminated, 1 current. thereforbeingsupplied through contactor" be stopped byfthestalling of motor |5as the door' encountersithe upper limit of its range of movement; .Asinthe case of the circuit arrangement of Fig. 1, the system is left'inthe* same condition whether the door is stopped at anin-"ftermediateposition by momentary depression and 'release of switch i7 or isVstopped at the topi of its travel bythe motor stall action; and ineither case, the double-throw rswitching relay is left in theconditionwith its arms thrown` to the opposite throw positionyto'providefor opposite propulsionV at the next .operation-i.v e..v

for downward propulsion.

Taking iirst the acase of stopping the door during its'upw'ard travelthrough the employment! of Vswitch VI '1,' the depression'of this'switch'iagain openscontactor IIOC and closes fcontactorsvA,..

B and D of relay I I0. Withithis closurefof contactor HOA, a shortingcircuit is provided from supply main 3| through contactor |300 'andcontactor I| I Afplacing terminal |28 atthe same potential as theopposite terminal of the coil of relay I20,land thus' deenergizing this.relayland breakingI its holding circuit through contactor |20B andresistor 35, the fullalternating current line voltage momentarily beingvplaced across resistorv 35.M With'the opening of contactor I20B,

the circuit through' conductorv |23 is' opened,

.and accordingly the energizationfor 'the vrun- .nin'gwinding of. themotor VIllis interrupted, causingthe system'to come to a stop; Relay |30f vremains*energizedatthis time, itscoil circuitl being supplied-nowthroughicontactors IB` and |30E,' frorrr` a time immediately prior to"the openin'gof Vcontactor HUG. Relay IGIJis nowl energized; the?circuiti` therefor' being traced through?contactorlA |50A fand re'closedcontactor I20E. -'Il1'erefore','v contactor I 60A is closed.lNow,fup`on!the release of switchlflgrelay'l III again"deenergizedf andrelay l|30 is 'thereupon 'deeneigized 'as a resultV of the opening ofAcon 'tactorl ISB inview-of -the open condition4 of contactorlZBG.Relays Ifand |60 remain energized, and larms'jI'll vand |62accordingiyre main'in-theirlower positions for downward-di-` rectionpropulsion, and lamp 25 remains on.

If; instead of the-operationv of switch I1 to-`ar' rest the'upwardtravel ofthe door-"atfan finter-y mediate position, theim'otor-I5 werepermitted' to propel the door to the top 'of its range'of'mo'vement,'thereclosure ofl switch? 2|V upon'the stallfjply circuit of conductor Ialso is opened by the opening of contactor |20B. The opening ofcontacter v breaks the holding circuit of relay |30, so that this relayalso is released. The reclosure of contactor |20E completes a circuitfor the energization of relay |60, through contactor |50A ci energizedrelay |50, and thus the same circuit conditions exist with the arms |6|and |62'o'f relay |60 in their downward throw, with lampe 25 illuminatedand with relays |50 and |60 en-' ergized, as resulted after momentarydepression and release of switch |1 to arrest the door at anintermediate point in its upward travel.

Now, the door may be started downward by a further momentary closure ofswitch l1, again energizingr relay ||0. Through this relay, relay |20 isagain energized, and the motor I5 is energized through contactor |20B,this time with the running winding connected in the`- opposite sense tothe supply mains for reversedirection yoperation to drive the doordownward. "Through relay |20, a circuit is this time provided 4forshorting the supply to the coil of relay |50, lthis circuit being tracedfrom supply vmain 3|thr'ugh downwardly deflected contact arm I113|,through 'contacter |20F to the upper terminal 228 of the coil of relay|50, the opposite end ofwhich -is xedly connected to the circuit ofsupplyinain 3|. Relay |50 is thereupon deenergized but re-n` lay |60-vremains energized throughgcontactor |60A and contactor |20G. p The.motorv l5 having commenced drivingthe ldoor downward andspeed-responsive switch 2| shaving f opened, the release of switch|'1'again turns off relay ||0, but relay |20 remains energized by virtueof its holding*l circuitf'through contactor 120B and resistor 35. PJelay |30-is nowk energized once more through-'contactors |20C'and||0C`, to remain thus energizedydur ing the downward propulsion ofthedoor;

` Just as in the case of upward propulsion'the downward door travel maybe stopped liric`l`-fiihe circuits all restored to the conditionsYillustrated in Fig. 2, either by a momentary ldepression"of "ing ofm'otor |5. The starting winding'circuit I |20G immediately .ofthe supplyto the running winding ofthe motor Y 15azful1 cycle of operation of'relay' |60 being an obstruction, the reclosing' of speed-responsivetactor |C breaking the energization-circuit of relay |30 immediately.

Thus, it is seen that relays |50- and |60 coactto provide the'eiect of acyclical phase reversal time'daccording to two-full, cycles ofoperation'of lrelay |20, and relay |20' being timedto one'cycle ofoperation with two cycles of relay ||0,in the same manner as relays 20*and 30 of Fig. lare arranged for two-to-one step-'down cycling relativeto the operations `of relay I0 of thatlgure.

VThe control system `*of Fig. 3 provides control of motor I5 in the samegeneral way as'lthejgarrangements of T Figs. l and 2, in thatcyclical'control is provided for starting the motor to driveV the doordownward'inresponseto a'rst signal K impulse, stopping its descent byasecondysignal impulse, starting the motor in the opposite direction todrivey the door upward inresponseftofa third signal impulseiand stoppingits ascent byja fourth signal impulse, the initial circuit conditionsprevailing for the subsequent commencejment. of a'complete'cycle ofoperation.; :Like the prior embodiments, the system ofxv Fig. 3; ar-

switch k|1 followed by its release providing an v intermediate stop ofthe door, or by thestalling of motor 5 upon full closure of thefdoor."Again describing the operation commencing withdepression of switch I1,the closure of this switch provides energization' of relay |10,Iand'relay |20 is thereupon released due tothe short-circuiting of itscoil through contactors 130C and ||0A. This provides for thei opening ofthe running winding circuit bythe opening ci contactor |20B. and forsafeguarding `against energization of the starting windingfby'the opencondition of the same contactor.

Relay remains deenergized and relay |30 remains energized, but relay isdeenergized by the opening of rcontactor |20G at" this time whilecontactor |50A remains open. Accordingly, double-throw armaturereversing circuit arms |61 and |62 of relay |60 are released 'totheir'upward throw position, preparing the circuit for upward propulsionat the next actuationffof inotor |5. H

`The release of` switch I1 again deenergiz'esjjrelay 0, resulting in thedeenergization ofi` relay |30 due to the opening of contactor ||0B,"contactor |20C also'being open. Now, the circuit conditions existasrshown in-Fig. 2.

The circuitconditions similarly are provided ranged for the stalling ofthe-motor when-'the door descends to its limit to serve the same purposeas the second impulse, setting up thel cond-itions for the system toreceive the third signal impulse and respond properly"theretoiiandsimilarly for the vstalling of the motorjat the upper limit of the doortravel to providelI circuit operationsv equivalent to `the signallingyyofthe fourth impulsev of the above-recited cy :le

In Fig. 3, two voltagev step-down transformers 212 and 2|3 withtheirprimary windings both normally energized and theirlow-voltagesecondarywindngs 2 I5 and 2|6 connected in seriess fcppositicn'are provided for the control circuit of themomentary-actuation low-voltage A. C. re-

lay 2|0`. A resistor 2|4 is includedin seriesjwi-th secondary 2|5, andthe momentary-wontact switch I1 is connected for eifectinga momentaryshort-circuit across the series combination; of

winding 2|5.and resistor 214. -When switch |1. islclosed, therefore, thecoil of relayjZlisvsup-k` plied directly by winding 2|6, and hencetherel lay is" actuated with its contactors2 |0 and 2 |0B bothmomentarily closed. fr

Stepping or sequence relay 210 is providedfwith a D. C. actuationcircuit'including recter 23 and capacitor 20, connected to bej'actuatedthrough contactor,2|0A. Contactor 2|0BL shortvcircuits-resistor 22'eachtime switch |1Y is depressed.U

Relay 210 includesv a rst stack of contactors 21|, 212 and 213ganged-together, a secondstack of contactors 214, 215and 216 gangedtogether, and one additional contactor 211. The conditions of thecircuit elements as 'illustrated' in Fig. 3 are the conditionsprevailing with the` garage door at the upper limit of its travel,andwith the rmotor turned off. The contactors of the rst and secondstacks are all open, but contactor"211 is closed so that thev lamp 25 isilluminated.`

Switch |1 is momentarily depressed to start the door downward. Thismomentarily shorts winding 2|5 and resistor 2M out of the circuit of thewinding of relay 2|0, leaving the fullyoltageof secondary 2|6 toenergize this relay and provide closure of contactors 2|0A and 2|0B.vTheprimary supply circuit of relay 210`is then Venergized harmature-carnof-this relay is advanced vfrom its l J'initial position tov its-secondposition with the rst stack of contactors-21I, 212 and 213 closed fland' contactor 211 also remaining closedthe conyfta'ctors of the secondstack remaining open.l

*With Vtheclosure of contactor 213, the series `fcircuit'of startingwinding I9 andspeed-respon- 'sive switch 2I is` energized with theswitch endl ofthecircuit connected to supply main 23| and the Yrighthandend of thestarting winding connected to yconductor 232".in circuit withVtheop- 'positelfsupply main 1232; '.'Running winding I8 of the-motor Ivis connected betweenrr thesupply ymains, the upper .end offthis windingin series "withl'resistorf 22Lbeing connected through con- -'tactorlZlI. to'conductor 23I and the lower end of winding I 8 being connectedthrough contactor 212 jtoiconductor'l232'. *Until ythe motor acceleratesib'eyond'the intermediate speed for which switch "2l isv preset, thisswitch remains closed, and through it and 'contactor 213; the primarywinding of1 transformer 2I2 is shorted out, retaining *relay 2`I 0-Ienergized even 'though switch I1 may bereleasedlhefore the motor i5 hasaccelerated appreciably 'During this'time, contacter ZILBshorts-resistorZZ out of the running winding cir- -cuit,-and the motoris thus started oil in the di- "rectionfdriving the doorY downward withYfull -torque. Themotor very quickly accelerates bei yond thefspeed atAwhich switch 2I is opened, and lwiththeopeningof this switch and theopening f switch'fl', the motor continues in itsy steadyvstate operatingconditions, driving the door downf ward'withrjust winding I8 energized,and with the torque limiting resistor 22 in circuit therewith.

" --Asin'th'e previously described embodiments of "this invention,`themotor I5 may be deenergizeol by? a depression-of switch 'I 1before thedoorreaches *the'dower limit of its travel, or alternatively, the arresto'flthedoor at this lower limit may be re- *lied' upon 1 for Hautomaticldeenergization of the 'frnotofff thedeenergization is accomplished byuseof'switch v"I1, this switch is momentarily 'closedfftof'shortsecondary'2I5 (and resistorv 2M) 'outof-"the primary circuit of relayZIO, leaving =a net/effective voltage for momentary actuation 'itlier'eb#With the momentary closure of confjtactor 219A; the cam system of relay210 is ad# Ivarice'd'to its third position at Awhich all contactorsofthis sequence relay are open, With -fthi'sfconditiom all circuits ofthemotor I5 are open; andthe lamp 25 is out.

`IffsWitch I1 is not employed for arresting the 'downward travel of thedoor at an intermediate "position, motor I5 drives it on downwarduntilit encounters the garage floor or apron, or any object offeringappreciably increased resistance to the'descent of the\door, as avelocipede or childs WagonA or a bank vof iceas may be presentv in-winter conditions. Thereupon, motor I5 is stalled.=and switchv 2Ithereof recloses, shortcircuiting the primary winding of transformer 1-2I21throughcontactor 213, and thereby removing 'xthaA secondaryvoltage. thereof from the circuit I ,Jof 'relay 2 I 0 just aseffectively .as if thesecondary windinglZI 5had been momentarilysnorted. Y, A i net :operating voltage-is ,thus provided by trans--Iormeni2l3 foractuating relay 2ID; to cause the: .zadvancementof thevcam system of. relay 21Il` to '.thezthird vposition with all oontactorsopen, and ithusthesamecircuit conditions .are made to pre- --yalainjthiswayA as.` could have .been obtained by use-ofzswitch .I1 to stopthedescent of 4the door.;

12 A .further Amomentaryidepression of switch'.l I 1 may he.usedztoxfstart the -raising offthefgarage door. i Relay v2H) -is againAmomentarily energized,

. -temporarily'shouting out resistor 22, and stepping relay`210- toitsfourth cam positionywith'kcontactors214, v215,'.f21-Ii and211 actuated.'Both windings` of lmotorrj 5 are energized through l' thefcontactors'ofr'thesecond stack, viz. .contactors 21.4; 215i and. 216.irDue to .the cross-connections between contactors'21l and2'12 oftherststack and 214A and1215 of the Vsecond stack, the running Windingofgthe'motor I5 is energized inthezopposite vIzvhasensense,:sog-that the.motor propulsion is in thefopposite'direction forupwarddrivefoi thedoor. I gAgain; thesupply of thestartingfwinding; I9 isinterruptedhy`theY opening'oflswitch 2I as the motor accelerates, theresistpr'xliyisirestored to effectiveness riny the l,circuit of therunning Iwinding with the; release of' switchil'H.

The arrest of, lthewmotor'l actuationAA circuits is accomplished eitherby; use of `switch I I7 f or :by the operation -ofswitch' 2 I i ,uponstallingkof'the motoras -thedoor reaches :the upper ,limit 'of-'fitstraVeLi the cam system.` of -relay^210z beingcadvanced fromi-ts fourthposition-to aposition corresponding to the -rst position;withwconta-ctor 211retained closed and the remaining contactms open, sothat the' 'lampl 25y i remainsonv andfthe motorfcircuits areaallinactive.

. One practical lform ffor-relay2fl0=is illustrated .,.in'Fign 4, ascomprising-.an angular-motion solenoid motor 290 coupledythrougharatchetIsyslterrito a series of threefcams '29I,.2S2-;andpf283 Aupon 4a commonsnafu-29,4, and arrangedtoraccomplish. af vBtl-degree;l angularadvancementgfof thev three-cam system with eachyractuationfiof `the,angular-motion;solenoid: motor. Onefcornplete cycle'of the 'operationsof the' garage;- door Y is accomplished with four 30o-degree: steps ofithe 4I) -cani'systemfor 120 degrees rotation'thereof, and the next;cycle of doorfvoperationsisaccomplished `with asimilar-series ofourf,-degree-vsteps, three sequences of similarlsets of four :coni/actoractuation steps'- being. providedginvone complete revolution of thecamsThe vthermal cut-out I 4 inf motor I 5 serves-not I only as asafetyfeature for protecting themotor the thermalrcut-outfthe. .contactortherein-is .opened f but also as a-devicefor oorrectingthe cycling ofthe. system ifthe -relay .sequence somehow gets 50.

..Assuming kfor example, that' the'door is Aatrest out ofi-stepwiththefoperationsot` the'fdoor.

at rthe lower 4limitY of its travel and -thatanf actuaf,tionoft switch fI1Y and 4relay-2l() bringsy about Ysuch an advancement of the cam systeminrelay of therst stack, thermotor :I5sis Menergizedin the sense todrive the-.door downward. Asthe door cannot yield` in .this direction,themotor remains completelyv stalled. :With the resultant .excessivecurrent through the resistance coil -of This-removesthe power yfromallfpartsfof the l,cont-rolsystemleaving the rstr`^ stack 's of con- -v.cut-'outwunit I4 has cooled its contactor-autotactors. -21I,213 `ofrelay, 21 U `closed. ..When-,the

matically recloses. Relay 2I0 must againrbetactuated,y whetheror notswitch I1-Vhasremained depressed, :because the circuit/tllrqllghi`@switch ,70.

closed .contactors shorts 1 out the primary circuit 2I .and-the bottomv-conta'ctor,off-,the s tackgof of transformerl2l2. Y Thus, relay-210isslepped immediatelyrzupon ,'the-reclosure of thermalcutoutgllfllhereafter,

the. nextl momentary r` energization, or switchrjl serves to startthesyste f withjpropulsion*of-the door'in the "correct directionifTheoperation of `-cut out I4 serves similarlyfor out-of-step operationat thel opposite` terminal'position-5l of the y door. Y

* is many changes could be made in the-above v construction' and manywidely diiferent'embodiments of this invention could-be made withoutdeparting 4from the scope thereof, it is intended that all mattercontained in the above description or shown -in the accompanyingdrawings s'hall be-interpreted as illustrativeand not in a limitingsense.

whats-cimmed is: i'

' A eontroifsystem for propulsion i an 0b ject between viirst andsecondlimits of travel #thereon comprising'a reversible Velectric motor"coupled tosaidobject, aV control circuit ytherefor in'cluding a switchcircuit, meansin said lconqtrol-ircuit responsive to a-mor'ne'ntaryclosure of isaidswitch circuit when said object -is at saidl"first:limit of'its travel `forfproviding sustained energization ofsaid motorffforfoperation in.r the direction driving l said-'object'toward said second limitI `of` its travel, means in saidcontrol-circuit rsponsiveto a momentary closure of saidswitch 1circuitwhile said object is being propelled to- -'ward saidsecond limitof itstravelfor deenergizing said electric motorandlconditioning the control-.sy`stem to receivea-f-urther inputs-circuit "closure forinstitutingpropulsion 'of Vsaid object `tov'vafrdfsaid first'limit ofitstravel, means A`in -'said-c'iontrol circuit responsive toA thefreactiofnof said -electric motor to the! increased propulsion resistanceuponarr-ivalofsaidobject at said-seclond limit-of itstravel fordeenergi'zing said Telectric motor and conditioningsaid fsystem toreceivea furtherswitch circuit closure for institut- 'ing-propulsion ofrsaid object toward said first-I li-1`nit of-'its travel, -andmeans insaid'control circuit responsive toa momentary closurefoif said switchcircuit i after l arrest 5 of propulsion of said object toward'v saidsecond limit of'its `travelfor instituting operation of said electricmotor in? the directionoriving said object towardI said first limit ofits travel,k c

2. A controlsyste'm as defined in claim l, iurther including means forautomatically arresting the propulsion of said objecttoward said firstlimit of its traveland conditioning-the control system to receive afurther switch circuit closure f or instituting propulsion of saidobject rtoward erein saidlast-named means comprises switch rhesus?actuated by said object in the vicinity of said rst limit of its travelfor deenergizing said electric motor and providing a reversed-directionstarting circuit therefor and maintaining said reversed-directionstarting circuit intact while said object is in the immediate vicinityof said rst limit of its travel.

4. A control system as defined in claim 2,

wherein said means for automatically arrestingv klimit positionL jectselectivelyirom a'rst limit positionto a second limit position and fromsaid second limit positionto said first limit position comprising areversible electric motor mechanically coupled-.to

said movable object, an electric power supplying 'circuit connected tosaid motor and includinglan impulse receiving circuit, means responsive'to-fan impulse received therein whensa'id Objectis in said firstposition for providing sustained electric energization oi said motor todrive saidobject from said first limit position to said secondlimitposition, means in said electric power supplying circuit responsive todecreasedspe'ed of the motor due to the increased resistance to travelof said object as said' object reaches said second limit position fordeenergizing said vmotor and leaving said electric power supplyingcircuit in condition to be energized for propulsion of saidobjecttowardsaid iirst limit position, and means responsive to a further impulsereceived in said receiving circuit when said object isin said secondklimit position for providing sustained electric energization of saidmotor in the sense'to drive said object vfrom said second limitposition-to said 'first :6. A system for propulsion 'of an objectbetween rst-and second limits of travelthereof, comprisiri'gareversibleelectric motor mechanicallycoupled toV said object for drivingit towardone-or the otherV4 ofv said' limits, a power supplying andcontrolling circuit for said motor including means for selectivelymaintaining four ysuccessive fcircuit conditions therein, the Liirst Icircuit condition (havving the'motor deenergiz'ed with theobjectat'theiirst limit of its' traveLLthe second circuit condition; having themotor energized` to operatein the direction driving'the object toward'.,the second limit of its travel, the'third circuit condition-havingthe motor deenergized with,l the :objectat'the second limitof itstravel, andthe ourth'f'circuit condition having the motor energizedto-operate in the direction driving the 'object toward the `fdr/st limit-of its travel, electric impulse: means connected insaidl powersupplying .and controlling Vcircuit and'operableduring anyone; ofi, saidfour -circuitgconditions for Yadvancing itto .theknext of saidrsuccessive circuitfconditions, and.- means ,responsiveto al speedreduction 'of said motoradue .to increased load thereonfor advancingsaid conltrol circuitfromoneof said conditions with the Amotor energizedto thenext conditioncwiththe 'motor deenergized.

7o. controlsystemas definedA in claim, 6-,1 said power supplying andcontrollingcircuit including r55- a'iiir'st relay responsive=to`saidelectric impulse means, secondl and third relays connected for operationthrough said first relay, and a sequence relay connected forstep-operation through the armature of said second relay upon releasethereof, said reversible electric motor having a running winding and astarting winding and a speedresponsive switch connected to said startingwinding, said four relays and said motor being deenergized and saidspeed-responsive switch being open when said object is at one limit ofits travel and said sequence relay including doublethrow armaturereversing switch means in connection with said motor in the sense foroperation of the motor in the direction for driving said 0bject towardthe opposite limit of its travel, said first relay being energizedcoextensively with the operation of. said electric impulse means, saidsecond relay being energized through said first relay upon energizationthereof, and including a holding circuit for maintaining itselfenergized after the impulse energization of said rst relay,

entrees :tactorconnected in series with an armaturecon f tactor. of saidiirst relay fordeenergizing said sec- ,.ondrelaywhen said rstand thirdrelays are both energized jwhereby said; second relay is deenergizedupon actuation. of said input circuit; during :propulsion of,said-object and said third relay is deenergized upon d eenergization ofsaidginput '-circuit.

8. Agcontrol; system as dened-in -cla-im ,rlsad ;power supplyingandcontrolling circuit including a rst relay responsive to said electricimpulse :means .second and third lrela-ys connected for l operationthrough vsaid V,firstrelay, and VYfourth and fifth re laysconnecte d foroperation vthrough f the armature of said second relay, said reversible.electric lmotor having a running windingv and a :.-1tartir xg winding,and avspeed-responsive switch :connected to said starting winding, saidvere- Al-aysand said motor beingdeenergized when said 1 object is at.one limit of its travel, said first relay being energized coextensivelywith the operation of said electric impulse means, said second relaybeing energized through said first relay upon energization thereofandincluding a holding cir- .cuit'for maintaining itself energized afterthe impulse -energization ofA said first relay, said third trelayhavingan energization circuit connected to the armatures of saidrst and secondrelays to'be operated upon deenergization of said rstrelay With-.saidsecond relay remaining energized, said lthird relay including a holdingcircuit maintained :through alternative paths through the armatures s ofsaid rst and second relays while either of said 1 firs-t and secondrelays is energized, said third 1 relay. also including an arma-turecontacter con- A-nected in series with an armature contacter of said rstrelay for deenergizing said second relay when said input circuit isactuated during a period When both -said secondand third relays areenergized, whereby said -third relay is deenergized upon thedeenergization of said first relay, 0

said.- fourth andj fifth relays being interconnected with armature.contactors .of ,said` second relay-.in -thesame. manner assaidsecond.andthirdrelaya respectively, arejinterconnected .witharmaturecont-actors of said rst relay, said second relayinrvcluding at leastonerarmature.contactoncon- ,nected in circuit Withi saidmotorrforholdinglthe Vmotor .circuit open'when said-secondrelay isdeenergized,andsaidfffth relayincludinggarmature contactors. connected for4reversing ;the feed circuit connections of .one windingofsaid. motor forreversingv kthe .propulsion thereoffwhenfsaid fth relay is energized. Yl

9. A control system as deflnedimclaimssaid power supplyingrandcontrollingircuitincludins g a rst .relayI kresponsive to, saidelectric` impulse meanssequence stepping relaymonnectedftotthe armatureof said Vfirst relay to .be- .advanced-fone step uponeach energizationthereof, .Sadrreversibleelectric motor, having@ running windingrndastarting Windipgand a speed-responsiveswitch connected to saidstartingWinding,-4 saidsequence stepping relay having a frstset of contactorsconnected to saidgmotor for .supplying the :Windings thereoi inthephase,` for `propulsion ofgsaid object "toward Asaid second. limit .ofits .travell-and a second set of contactors connected tocsaid motor .forsupplying. the 4windings .thereof in .the phase/for propulsionfof-said object toward said first limit. of its j travel, ,said ysequencejsteppingrelay including yfour-stepsin yonecycle of its operation, wi-thf saidrst setof contaotors operated at thelrststen saidiirst and second setsof contactors beingreleased at the second step, Said -second; -set vofcontactors .being operated -atthe third step, and said first-and secondsets of con- .tactors being released atthe fourth -step, and

said power supplyingand ,con-trolling circuit :including coupling lmeansbetween saidyspeedrresponsive switch and said first relay for energizingsaid -first relay whilesaid speed-responsive switch is initsloW-speedthrow and one of saidfsets of Ycontactors `of `said sequencestepping `relayis operated.

GEORGE F.' RICHARDS.

4mnuiRENcEs err-E1) The following references are of recordfin the fileof this patent:

YUNrrED STATES PATENTS Number 5 Date Gower Aug.. 12, `1947

